For example, asio::async_connect(), the documentation doesn't provide the possible error codes that could result.
It does provide a bunch of error_codes and a brief explanation, but is doesn't tell me which errors the async_connect function could send to the handler. Basically, I want to know if this error is something that can be recovered or not.
I'd rather not have to go through all the errors for every handler to work out whether it can be recovered or not. My reasoning is that sometimes, depending on the situation error_x might be recoverable, other times it's not.